Sanity Check - VOIP VLAN 3CX

[Olliedawg]

Finally getting around to moving our IP phones & PBX off our main network... Am i on the right track here? 

3CX, Yealink T4xS phones, Mikrotik/Neatgear switches

 

Created a new VLAN specifically for VOIP (ID 500)

 

Tagged trunk ports where required from core to edge switches

 

Firewall will be handling DHCP, so to provision phones I've set DHCP option 66 to https://my-domain.3cx.co.uk:5001/provisioning/p8l5401x6ju

 

On our edge switches to the phones, should I be leaving our Data VLAN untagged, and tagging the VoIP VLAN from the switch to the phone? Then configuring the phone to set the WAN port to the VoIP VLAN and the PC port to the Data VLAN?

Edited April 7 by Olliedawg

[CrootUK]

If your PBX is in the same VLAN you dont need option66 in dhcp as it uses multicast btw. 

 

That’ll only work if you configure on each provisioned phone in 3cx the VLAN it should use other wise the phones will just sit in the untagged vlan. 

 

Ideally you want to be using LLDP here and have the switches tell the phones what VLAN to use but I dont know what options Mikrotik/Netgear switches have around that. 

 

 

 

 

Edited April 7 by CrootUK

[Olliedawg]

14 hours ago, CrootUK said:

If your PBX is in the same VLAN you dont need option66 in dhcp as it uses multicast btw. 

 

That’ll only work if you configure on each provisioned phone in 3cx the VLAN it should use other wise the phones will just sit in the untagged vlan. 

 

Ideally you want to be using LLDP here and have the switches tell the phones what VLAN to use but I dont know what options Mikrotik/Netgear switches have around that. 

 

 

 

 

Ahh didn't know that regarding the multicast - good to know! Our PBX is in a different VLAN so i'll leave that as it is

 

That's ok, i'm going to test the config with a few phones & then i'll look at making a new template to re provision all the other phones with the same settings.

[AlphamaleZed]

Option 132 - VLAN ID for VOIP

Option 160 - Prov URL

 

Then set them to tag for all VOIP on every VLAN.

 

This works and tested for yealink.

[Davit2005]

On 07/04/2026 at 15:45, Olliedawg said:

Finally getting around to moving our IP phones & PBX off our main network... Am i on the right track here? 

3CX, Yealink T4xS phones, Mikrotik/Neatgear switches

 

Created a new VLAN specifically for VOIP (ID 500)

 

Tagged trunk ports where required from core to edge switches

 

Firewall will be handling DHCP, so to provision phones I've set DHCP option 66 to https://my-domain.3cx.co.uk:5001/provisioning/p8l5401x6ju

 

On our edge switches to the phones, should I be leaving our Data VLAN untagged, and tagging the VoIP VLAN from the switch to the phone? Then configuring the phone to set the WAN port to the VoIP VLAN and the PC port to the Data VLAN?

Yes you would normally tag the traffic on the switch port connecting to the phone then untag the normal data traffic which normally just passes through the phone. Don't forget to set the vlan to voice mode on the switch where the endpoints (phones) are connecting 🙂

Edited April 9 by Davit2005